1. Field of the Invention
Embodiments relate to an apparatus for producing an endless filter rod of the tobacco processing industry that includes a transport nozzle that can be loaded with compressed air and a guide tube with an elongated rod arranged in the guide tube. An infeed roller that is not driven but rotates freely is arranged directly at the end of the transport nozzle and at a distance to the rod, and a bearing surface of the infeed roller defines in sections the conveying path of the filter material web. Embodiments also relate to an endless filter rod machine and a method corresponding to the apparatus.
Thus, embodiments relate to the field of filter production, in particular to the production of filters with inserted objects, e.g., fluid-filled capsules. Such capsules are crushed by the user before the use of the cigarette, and while smoking the cigarette develop an additional flavor. Other types of objects can also be inserted, for example, further filter materials such as an active charcoal body, granulates, and the like can be inserted.
2. Discussion of Background Information
The most common method for inserting objects into an endless filter rod, in particular an endless filter rod made of acetate tow, includes that the objects are held at the periphery of an insertion wheel in object seats applied with suction air, and that plunge into the endless filter rod with the periphery of the insertion wheel in the course of the rotation of the insertion wheel. At the transfer point in the endless filter rod, the suction air is shut off and the object remains in the endless filter rod. For this purpose, the endless filter rod has a U-shaped cross-section at the transfer location so that the objects can be reliably inserted into the endless filter rod with low stress. An appropriate object insertion apparatus is known, for example, from the applicant's patent application EP 2 502 510 A1, the disclosure of which is expressly incorporated by reference herein in its entirety.
In order to bring the endless filter rod, or respectively the filter material web into the required U-shape, the filter material web, in particular the tow strip, is conveyed through a transport nozzle with an excess of compressed air. The transport nozzle, in addition to the drive of the conveyance, serves also for gathering the previously outspread filter material web into an endless rod shape with low density. The still loose endless rod is then inserted into a tow guide which is inserted from a guide tube with an elongated rod arranged inside, also called a plow. The combination of the rod and the guide tube arranged around it ensures that the loose endless filter rod in the guide tube wraps around the rod, and the endless filter rod thusly obtains the necessary U-shape into which subsequently the objects can be inserted from above.
With the apparatus according to the document EP 2 502 510 A1, the loose endless filter rod arrives after the conveyance through the transport nozzle on an infeed roller which turns the endless filter rod around and has a substantially U-shaped or V-shaped circumferential profile, that bends and folds the filter material while it runs over the infeed roller. The infeed roller has a relatively large radius of the bearing surface and is arranged at a distance from the beginning of the rod that is bridged by the endless filter rod. Here, the beginning of the rod means the end facing toward the transport nozzle, thus, the end located upstream in the conveying direction of the endless filter rod, also called rod projection and rod projection part in the following in the scope of the present invention. This section of the rod has a plow-like curvature and, where appropriate, a flat blade edge that serves for guiding the endless filter rod. The filter produced in this manner has a relatively low pressure drop compared to filters without capsules.